A high-precision sampling scheme to assess persistence and transport characteristics of micropollutants in rivers

Abstract

Increasing numbers of organic micropollutants are emitted into rivers via municipal wastewaters. Due to their persistence many pollutants pass wastewater treatment plants without substantial removal. Transport and fate of pollutants in receiving waters and export to downstream ecosystems is not well understood. In particular, a better knowledge of processes governing their environmental behavior is needed. Although a lot of data are available concerning the ubiquitous presence of micropollutants in rivers, accurate data on transport and removal rates are lacking. In this paper, a mass balance approach is presented, which is based on the Lagrangian sampling scheme, but extended to account for precise transport velocities and mixing along river stretches. The calculated mass balances allow accurate quantification of pollutants' reactivity along river segments. This is demonstrated for representative members of important groups of micropollutants, e.g. pharmaceuticals, musk fragrances, flame retardants, and pesticides. A model-aided analysis of the measured data series gives insight into the temporal dynamics of removal processes. The occurrence of different removal mechanisms such as photooxidation, microbial degradation, and volatilization is discussed. The results demonstrate, that removal processes are highly variable in time and space and this has to be considered for future studies. The high precision sampling scheme presented could be a powerful tool for quantifying removal processes under different boundary conditions and in river segments with contrasting properties.

Influence of Emission Sources and Tributaries on the Spatial and Temporal Patterns of Micropollutant Mixtures and Associated Effects in a Small River

“…To address hypothesis 1), each tributary and the main stem were investigated by grab sampling. For hypothesis 2), we followed individual water parcels using a Lagrangian sampling technique (Writer et al 2011;Schwientek et al 2016).…”

Comparison of environmental tracers including organic micropollutants as groundwater exfiltration indicators into a small river of a karstic catchment

“…The analgesic tramadol for example was described to undergo attenuation processes in a river (Li, Sobek, & Radke, 2016), whereas other studies indicate a conservative character(e.g., Glaser et al, 2020). Concentrations of WWTP‐derived compounds in small rivers often show a diurnal signal due to changing discharge from the WWTP (Schwientek et al, 2016). To distinguish advection of the transient concentration signal from actual loss processes, Lagrangian sampling is necessary for the quantification of processes affecting pollutant fluxes and concentrations.…”

“…Organic micropollutant concentrations (sulfamethoxazole, carbamazepine, ibuprofen) were used as anthropogenic indicators in the hyporheic zone (Banzhaf, Krein, & Scheytt, 2012) and to understand GW–SW interactions in a lowland Chalk catchment (Manamsa, Lapworth, & Stuart, 2016). A prominent example is carbamazepine which is often considered conservative due to its long half‐life compared to the travel time of river water (Guillet et al, 2019; Kunkel & Radke, 2012; Pal, Gin, Lin, & Reinhard, 2010; Schwientek, Guillet, Rügner, Kuch, & Grathwohl, 2016). The persistent behaviour of a selected compound is indispensable for its successful application as a tracer, but the persistence may be river‐specific.…”

High-throughput evaluation of organic contaminant removal efficiency in a wastewater treatment plant using direct injection UHPLC-Orbitrap-MS/MS

“…† The samples were analyzed in triplicate and each sample was injected three times, as multiple injections have been proven useful in reducing false positive results and in partially correcting for false negatives generated during the peak picking step in the non-target analysis protocol. 30,31 2.5. HRMS data post-processing workow All HRMS data were processed using Compound Discoverer 2.1 (Thermo Scientic).…”